The present inventions relate to improvements in tools and methods used in subterranean wells used to manipulate downhole apparatus. More particularly the present inventions relate to a downhole fluid powered tool which can be placed in a well and utilizes downhole pressure differentials to power the tool and use it to manipulate downhole apparatus.
Devices located downhole in a well that require downhole manipulation include packers, valves, side doors, and the like. Some of these devices are pressure actuated or manipulated. For example production packers are run in a well and moved from an unset to a set condition by temporarily plugging the production tubing and thereafter increasing the tubing pressure to move a piston in the packer assembly. Setting pressures are limited by the capacity of the available pumping equipment and by the safety pressure ratings of the surface equipment and production tubing. It is not unusual to find well operators that limit surface and tubing pressures on their wells to 3000 to 4000 psi for use in setting downhole equipment. In such wells as those requiring larger bore hydraulic set packers with resultant small setting-piston areas, surface pressure limitations can result in setting forces so low that the performance of the packer may be compromised. Although more expensive specially designed packers such as those with dual setting pistons can be used, the associated increased costs are undesirable.
The present inventions contemplate an improved well tool actuator and method does not require more expensive downhole equipment and can be utilized with limited actuation pressures.
According to the improved well tool actuator and method of the present inventions, a fluid pressure intensifier, is placed in the well and coupled to the downhole device to be manipulated. Fluid pressure intensifiers are devices that are powered from a supplied pressurized fluid to produce a supply of fluid of higher pressure than the supplied pressurized fluid. Typically intensifiers have oscillating internal pistons or the like that produce a supply of fluid at a pressure increase of one point two times to twenty times the fluid supply pressure. By using a fluid pressure intensifier the actuation pressure can be increased to a pressure sufficient to operate or manipulate the downhole device without the necessity of increasing the tubing pressure. According to the present invention the actuation pressures supplied by the intensifier can exceed the safe operating rated pressures of the well tubings and equipment. The well tool actuators of the present invention are self-contained in that they are powered from the tubing fluid pressure itself without a high-pressure hydraulic or electrical connection to the surface.
According to the present inventions, subterranean hydraulically actuated well tools can be actuated at higher pressures than the supplied pressure. Fluid pressure intensifiers circuits can be assembled in and carried downhole with the actuation tool and removed once the actuation process is complete. Also, fluid pressure intensifier circuits can be assembled as a part of the well tool and operated remotely